The nuclear-polyhedrosis virus of Heliothis zea (Boddie) and Heliothis virescens (Fabricius) : III. Effectiveness of the virus against field populations of Heliothis on cotton, corn, and grain sorghum

Abstract

The nuclear-polyhedrosis virus propagated in larvae of the bollworm, Heliothis zea (Boddie), reared on a semisynthetic diet was effective against field populations of H. zea on grain sorghum, corn, and cotton, and the tobacco budworm, H. virescens (Fabricius), on cotton. A single application of the virus at 9.96 × 10 11 polyhedral inclusion bodies (PIBs)/acre gave effective control of H. zea on grain sorghum. Highly significant reductions in H. zea infestations on corn were obtained in three experiments with several applications of 6 × 10 11 PIBs/acre. In two tests against H. zea and H. virescens on cotton, the virus, applied several times at 6 × 10 11 PIBs/acre, compared favorably with insecticides recommended on cotton. In another test on cotton in which no insecticide was used, the virus, applied at 6 × 10 11 and 6 × 10 12 PIBs/acre, controlled heavy populations of both Heliothis species.